It is known that muscle contraction may be effected through electrical stimulation of the muscle and/or the appropriate nerve. In some instances, the stimulation is cycled in accordance with a preselected program. For example, the well known cardiac pacemakers stimulate the heart in accordance with predetermined requirements of heart activity which requirements are generally independent of the patient's activity. However, in other instances it is necessary to perform a switching function in response to a particular activity of the patient.
It is known that foot drop can be combated with appropriate electrical stimulation applied at the proper time. For example, when a patient with foot drop walks, the foot drop is most effectively overcome by applying stimulation when the foot in question, and particularly the heel, is lifted. The stimulation should then be stopped when the foot is again placed on the floor. Similarly, some patients require an artificially induced muscle contraction to allow them to stand without mechanical aids. The stimulation to provide this contraction should be applied while the foot is on the floor and removed when the foot leaves the floor. While one of these examples requires an artifically induced muscle contraction while the foot is on the ground and the other requires such a contraction when the foot is off the ground, it is apparent that an efficient device which switches between open and closed positions in response to the foot contacting and leaving the ground will be suitable for both.